Package org.jgrapht.traverse
Class BreadthFirstIterator<V,E>
- java.lang.Object
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- org.jgrapht.traverse.AbstractGraphIterator<V,E>
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- org.jgrapht.traverse.CrossComponentIterator<V,E,java.lang.Object>
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- org.jgrapht.traverse.BreadthFirstIterator<V,E>
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- All Implemented Interfaces:
java.util.Iterator<V>
,GraphIterator<V,E>
public class BreadthFirstIterator<V,E> extends CrossComponentIterator<V,E,java.lang.Object>
A breadth-first iterator for a directed and an undirected graph. For this iterator to work correctly the graph must not be modified during iteration. Currently there are no means to ensure that, nor to fail-fast. The results of such modifications are undefined.- Since:
- Jul 19, 2003
- Author:
- Barak Naveh
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Nested Class Summary
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Nested classes/interfaces inherited from class org.jgrapht.traverse.CrossComponentIterator
CrossComponentIterator.VisitColor
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Field Summary
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Fields inherited from class org.jgrapht.traverse.AbstractGraphIterator
nListeners
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Constructor Summary
Constructors Constructor Description BreadthFirstIterator(Graph<V,E> g)
Creates a new breadth-first iterator for the specified graph.BreadthFirstIterator(Graph<V,E> g, V startVertex)
Creates a new breadth-first iterator for the specified graph.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description protected void
encounterVertex(V vertex, E edge)
Update data structures the first time we see a vertex.protected void
encounterVertexAgain(V vertex, E edge)
Called whenever we re-encounter a vertex.protected boolean
isConnectedComponentExhausted()
Returns true if there are no more uniterated vertices in the currently iterated connected component; false otherwise.protected V
provideNextVertex()
Returns the vertex to be returned in the following call to the iteratornext
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Methods inherited from class org.jgrapht.traverse.CrossComponentIterator
finishVertex, getGraph, getSeenData, hasNext, isSeenVertex, next, putSeenData
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Methods inherited from class org.jgrapht.traverse.AbstractGraphIterator
addTraversalListener, fireConnectedComponentFinished, fireConnectedComponentStarted, fireEdgeTraversed, fireVertexFinished, fireVertexTraversed, isCrossComponentTraversal, isReuseEvents, remove, removeTraversalListener, setCrossComponentTraversal, setReuseEvents
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Constructor Detail
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BreadthFirstIterator
public BreadthFirstIterator(Graph<V,E> g)
Creates a new breadth-first iterator for the specified graph.- Parameters:
g
- the graph to be iterated.
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BreadthFirstIterator
public BreadthFirstIterator(Graph<V,E> g, V startVertex)
Creates a new breadth-first iterator for the specified graph. Iteration will start at the specified start vertex and will be limited to the connected component that includes that vertex. If the specified start vertex isnull
, iteration will start at an arbitrary vertex and will not be limited, that is, will be able to traverse all the graph.- Parameters:
g
- the graph to be iterated.startVertex
- the vertex iteration to be started.
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Method Detail
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isConnectedComponentExhausted
protected boolean isConnectedComponentExhausted()
Description copied from class:CrossComponentIterator
Returns true if there are no more uniterated vertices in the currently iterated connected component; false otherwise.- Specified by:
isConnectedComponentExhausted
in classCrossComponentIterator<V,E,java.lang.Object>
- Returns:
- true if there are no more uniterated vertices in the currently iterated connected component; false otherwise.
- See Also:
CrossComponentIterator.isConnectedComponentExhausted()
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encounterVertex
protected void encounterVertex(V vertex, E edge)
Description copied from class:CrossComponentIterator
Update data structures the first time we see a vertex.- Specified by:
encounterVertex
in classCrossComponentIterator<V,E,java.lang.Object>
- Parameters:
vertex
- the vertex encounterededge
- the edge via which the vertex was encountered, or null if the vertex is a starting point- See Also:
CrossComponentIterator.encounterVertex(Object, Object)
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encounterVertexAgain
protected void encounterVertexAgain(V vertex, E edge)
Description copied from class:CrossComponentIterator
Called whenever we re-encounter a vertex. The default implementation does nothing.- Specified by:
encounterVertexAgain
in classCrossComponentIterator<V,E,java.lang.Object>
- Parameters:
vertex
- the vertex re-encounterededge
- the edge via which the vertex was re-encountered- See Also:
CrossComponentIterator.encounterVertexAgain(Object, Object)
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provideNextVertex
protected V provideNextVertex()
Description copied from class:CrossComponentIterator
Returns the vertex to be returned in the following call to the iteratornext
method.- Specified by:
provideNextVertex
in classCrossComponentIterator<V,E,java.lang.Object>
- Returns:
- the next vertex to be returned by this iterator.
- See Also:
CrossComponentIterator.provideNextVertex()
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